An unwelcome visitor rolled onto the beaches of South Florida recently.
According to The Associated Press, the coasts of Port Everglades to Palm Beach were invaded by balls of tar, forcing some beaches to close for a time.
The source of the tar balls is a mystery, though they generally form from oil spills or underwater petroleum reserves. Though not overly harmful to most people, they can cause rashes and allergic reactions to those with sensitivity to chemicals.
The U.S. Coast Guard has ended its investigation into how these particular tar balls formed, though they are believed to naturally dissipate in time.